Understanding Sickle Cell Anemia
Sickle cell anemia is a type of sickle cell disease, a group of inherited red blood cell disorders. Healthy red blood cells are round and flexible, allowing them to move quickly through blood vessels. In sickle cell anemia, a mutation in the sickle cell gene causes red blood cells to become rigid and crescent-shaped, resembling a sickle.
These abnormally shaped cells are prone to clumping together and blocking blood flow (as illustrated in the image below), leading to various complications of sickle cell disease. They also have a shorter lifespan than normal red blood cells, which can lead to anemia. Anemia is a lack of red blood cells to carry oxygen throughout the body.
Causes of Sickle Cell Anemia
Sickle cell anemia is caused by a mutation in the HBB gene, which provides instructions for making hemoglobin—the protein in red blood cells that carries oxygen. To develop sickle cell anemia, a person must inherit two copies of the mutated gene, one from each parent.
If a person inherits one copy of the mutated or sickle cell gene and one normal gene, they have the sickle cell trait and do not have health problems. However, they can pass the gene on to their children.
Sickle Cell Anemia Symptoms
The symptoms of sickle cell anemia can vary widely in severity and may begin around 6 months of age. Common symptoms include:
- Anemia. People with sickle cell anemia often have low red blood cell counts due to the short lifespan of sickle-shaped cells, which can lead to chronic fatigue, weakness and pale skin.
- Frequent infections. Sickle cell anemia makes people more susceptible to infections because the sickle cells can damage the spleen, an organ that helps fight infections.
- Pain crisis. Vaso-occlusive episodes are sudden, severe pains caused by sickle-shaped cells blocking blood flow to specific body areas. These pain crises can affect the chest, abdomen, joints and bones.
- Swelling in hands and feet. Often one of the first signs of sickle cell anemia in children is swelling caused by sickle cells blocking blood flow to the extremities.
Complications of Sickle Cell Anemia
Sickle cell anemia can lead to a variety of severe and potentially life-threatening complications. These include:
- Acute chest syndrome. This is a severe lung condition resembling pneumonia caused by sickle cells blocking lung blood vessels. It requires immediate medical attention.
- Organ damage. Over time, repeated sickling and reduced blood flow caused by sickle cells can damage organs such as the eyes, kidneys, liver and heart.
- Delayed growth. The chronic shortage of red blood cells can slow the growth and development of children with sickle cell anemia.
- Stroke. Children with sickle cell anemia are at an increased risk of stroke due to blockages in blood vessels leading to the brain.
Treatment Options for Sickle Cell Anemia
Medications
While there is no universal cure for sickle cell anemia, several medications are available to help manage symptoms and reduce complications.
- Hydroxyurea. This medication can reduce the frequency of pain crises and acute chest syndrome by increasing the production of fetal hemoglobin, which helps prevent the sickling of red blood cells.
- Pain relievers. Over-the-counter and prescription pain medications can help manage the pain associated with sickle cell crises.
- Antibiotics and vaccinations. Medical providers may prescribe antibiotics like penicillin and recommend vaccines against certain bacteria and viruses to prevent infections, especially in children.
- Riociguat. Evidence from a research study led by the University of Maryland School of Medicine shows that a drug called riociguat may safely lower blood pressure for individuals with sickle cell anemia, helping to prevent pulmonary hypertension, stroke and kidney failure.
Other drugs are being tested as well, and clinical trials are available to those who apply and qualify.
Blood Transfusions
Regular blood transfusions can help increase the number of normal red blood cells in the body, reducing the risk of complications such as stroke.
Bone Marrow Transplant and Stem Cell Transplantation
A bone marrow transplant (also known as a stem cell transplant) is a potentially curative option for sickle cell anemia. In this procedure, a patient receives healthy stem cells from a donor, allowing the new stem cells to produce normal red blood cells. However, this treatment is not without risks and is typically reserved for severe cases.
Gene Therapy
In December 2023, the Food and Drug Administration (FDA) approved two gene therapies, Casgevy and Lyfgenia, for treating sickle cell anemia in patients 12 years and older. They are both cell-based gene therapies that use different methods to genetically modify the patient’s own blood stem cells, which are then transplanted to the patient during a blood stem cell transplant that uses those cells. Preliminary data show that these therapies are relatively safe and effective with few side effects, although blood cancer has occurred in some patients treated with Lyfgenia.
Preventing and Managing Complications
Managing sickle cell anemia involves preventing complications and responding quickly to health issues. These steps include:
- Avoid extreme temperatures. Both cold and hot temperatures can trigger a pain crisis. Dress appropriately for the weather and avoid sudden temperature changes.
- Try to avoid exposure to high altitudes. This includes flying, mountain climbing or visiting high-altitude cities.
- Try to avoid exposure to low oxygen levels. Situations with low oxygen levels include mountain climbing and exercising extremely hard, such as in military boot camp or while training for an athletic event.
- Wash your hands often. Cleaning your hands with soap and water often throughout the day will help prevent an infection. Encourage family members and caregivers to do this as well.
- Stay hydrated. Drinking plenty of water helps prevent sickle cells from sticking together and blocking blood flow.
- Get vaccinated. To prevent harmful infections, children with sickle cell anemia should get all of their childhood vaccinations, and adults should get their yearly flu and pneumococcal vaccines as well as any others their doctor recommends.
- Visit the eye doctor yearly. Starting at age 10, people with sickle cell anemia should get annual eye exams to monitor the health of their retina. The complications of sickle cell anemia can damage the retina and cause vision loss.
- Monitor for symptoms. Regularly check for signs of infection or other complications, such as fever, swelling or unusual fatigue.
- Develop a sickle cell action plan. Work with your medical provider to create a plan that outlines how to manage pain crises, when to seek medical attention and how to prevent complications.
Living with Sickle Cell Anemia
Living with sickle cell anemia requires careful management and regular medical care. However, with proper treatment, many people with sickle cell anemia can lead fulfilling lives. Those affected, especially children, must seek support from medical providers and family and community resources.
University of Maryland Medical System offers specialized clinics that treat patients with sickle cell disease, including:
- UM Capital Region Medical Center – in Prince George’s County
- University of Maryland Medical Center – in downtown Baltimore
Sickle cell anemia is a complex and challenging condition but advances in treatment and management strategies offer hope for improved quality of life. Whether through medications, lifestyle adjustments or stem cell transplantation, those affected by sickle cell anemia can take proactive steps to manage their condition and reduce the risk of serious complications. If you or someone you love is affected by sickle cell anemia, staying informed and working closely with medical providers to develop a comprehensive care plan is essential.
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Medically reviewed by Ivan N. Zama, MD.
